The present invention relates to medical electrodes used in conjunction with electrocardiograph apparatus and more particularly, to an assembly for dispensing the medical electrodes.
Medical electrodes of the foregoing type are utilized in a number of applications for a variety of purposes. The monitoring of physiological electric potentials to detect muscular activity of the heart muscle is generally well established, such apparatus being referred to in the art as electrocardiograph (also referred to herein as ECG) apparatus. The resulting traces derived from such apparatus provide a diagnostic tool for detecting heart disease and/or defects. The monitoring of physiological electrical potentials may be employed in a number of other applications. For example, a simple ECG test to obtain a single tracing for diagnostic purposes may be carried out in a few minutes in a physician's office. Hence, medical electrodes utilized for such testing may be of a relatively simple disposable variety, since they are only in service for a very short time. Conversely, longer term monitoring applications require that the medical electrodes remain in place on the patient's skin for considerably extended periods of time. For example, in stress testing, the heart activity of the patient is monitored over a relatively longer period of time while the patient exercises upon a tread mill or similar apparatus. Such testing may include monitoring of the heart activity during the exercise, as well as continued monitoring during the rest period thereafter so as to monitor the return of the heart to a normal or unstressed condition. Similarly, medical electrodes monitoring heart activity during surgery may be required to remain in place and operational for a period of several hours.
During one of these electrocardiographic examinations, medical electrodes are connected to electrocardiograph apparatus are affixed to the skin of a patient at the proper positions for heart monitoring. It is important to not only properly position the electrodes on the patient, but also, to do so without excessive handling. Any additional handling of the electrode increases the tendency of having the electrode contaminated or otherwise disturbed, thereby destroying or altering the electrocardiograph trace resulting from the examination.
A common medical electrode used for these purposes typically comprise a relatively thin backing layer, a metal layer and a tacky conductive gel. For example, an electrode having a polyethylene terephthalate backing member with a tin foil layer and a conductive gel may be used for monitoring a patient for short periods of time. These medical electrodes commonly include a projecting tab and are thus referred to in the art as tab electrodes. The tab electrodes are mounted in rows on a carrier sheet for storage and dispensing with their conductive gel layers pressed against the sheet. Such electrodes do not adhere well to the patient and are difficult to use. As a result, some tab electrodes leave the tab portion of the electrode uncoated with conductive gel so as to allow the user to grip the electrode before removal from the carrier sheet.
Some users attempt to attach the lead wire clip from the electrocardiograph to the tab of the electrode before removing the electrode from the carrier sheet. This method requires a significant amount of care and is not accomplished easily or quickly. In particular, the user must carefully separate the uncoated tab of the electrode from the carrier sheet in order to permit attachment of the lead wire clip. The user must then peel the electrode from the sheet, transfer it to the patient in the proper position without dislodging the lead wire clip. In view of the rather small, thin and slippery construction of the backing and metal layers, users are faced with a formidable task.
Consequently, some users attach the electrode to the patient and thereafter, attach the lead wire to the tab of the electrode. In this way, the electrode can be removed from the carrier sheet more easily. Many difficulties, however, present themselves to users employing this procedure. For example, the separation of the electrode from the carrier sheet is difficult in view of the adhesive forces between the electrolyte gel of the electrode and the carrier sheet. As a response to these problems, U.S. Pat. No. 4,798,208 provides an assembly for dispensing electrodes which includes a release web and a fold line allowing the web to be folded back along its longitudinal center, thereby exposing the tabs of the electrodes. The electrodes, however, must be disposed on the web in two rows with the tabs of each electrode in each row facing one another. Moreover, if the electrodes include tabs having a tacky material such as an electrolyte gel on their undersurfaces, the tabs are not easily exposed by merely folding back the web along its longitudinal center. Therefore, it would be desirable to have a more versatile assembly for dispensing electrodes including those electrodes having tabs with tacky undersurfaces.
Accordingly, there is a need for an assembly for dispensing medical electrodes used in conjunction with electrocardiograph apparatus which facilitates access to the medical electrodes such that they may be easily removed and placed on a patient. There is also a need for a versatile assembly for dispensing medical electrodes which facilitates access to the electrodes without substantially increasing the cost of such an assembly.